1. Field of the Invention
The present invention pertains to technology for wirelessly transmitting messages, such as CEC (Consumer Electronics Control) defined by e.g. the HDMI (High-Definition Multimedia Interface) Specification, for controlling video equipment such as e.g. DVD (Digital Versatile Disc) players.
2. Description of the Related Art
Technology in which video frame signals are sent from a video transmission device to a video reception device and CEC messages determined by the HDMI Specification are communicated wirelessly, bi-directionally, between the video transmission device and the video reception device is disclosed in JP-B-4116071, JP-A-2008-153826, and JP-A-2008-153827. In JP-B-4116071, there is described technology of replying by proxy to the transmitting party with an ACK bit indicating that it has been possible to receive data such as the registration of physical addresses and logical addresses or a CEC message, in the case of wirelessly connecting a video transmission device and a video reception device.
Also, technology pertaining to the transmission and reception of similar CEC messages is described in JP-A-2008-153826 regarding the case of two video transmission devices and one video reception device, and in JP-A-2008-153827, regarding the case of one video transmission device and two video reception devices.
In any event, in case the connection configuration of a piece of video equipment (e.g. equipment outputting and receiving video images such as a DVD player, an HDD (Hard Disk Drive) recorder or an STB (Set Top Box) having a tuner; there also being cases hereinafter where these are called “AV equipment”) connected with a video reception device changes and the physical address of the video reception device has changed, these also change the physical address of the video transmission device, being linked together. As for AV (audiovisual) devices connected by wire with the video transmission device, the physical addresses were changed sequentially in response to the change in the physical address of the video transmission device, and, in order to obtain compatibility of the physical addresses of the entire CEC system, some time was required until all the physical addresses had been determined.
Moreover, in JP-B-4116071 et cetera, it is described that, in the case of wirelessly transmitting a CEC message constituted by several bytes, a video transmission device (or a video reception device) with which a piece of AV equipment is connected by wire brings the CEC message to completion by replying by proxy with a reception confirmation ACK bit and further that, in order to avoid proxy replies to a CEC message toward the destination of a non-existing piece of AV equipment, the video transmission device (or video reception device), being the CEC message wireless transmission recipient, is served notice, in the case where the video reception device (or video transmission device) being the CEC message wireless transmission recipient is unable to receive a reception confirmation ACK bit from the destination of the CEC message, of the information about the same impossibility to receive, and the proxy reply operation destined for the corresponding address is stopped.
Here, the video transmission device (or video reception device) required time for checking that the destination piece of AV equipment did not exist and could not return a reception confirmation bit, in order to transmit in units of CEC messages composed of several bytes.